VLA observing proposals are refereed outside the NRAO before being considered by the scheduling committee. To receive high priority, the scientific goals must favorably impress a panel of external referees who read a hefty batch of such proposals at each competition. A ``highly-placed source who wishes to remain anonymous" notes that more concisely-written proposals are more likely to be refereed favorably, all else being equal. A good proposal will make it crystal clear what astrophysical questions are being asked, and how the specific measurements that are being proposed will answer them. It will also show that you chose the array configurations, observing frequencies, total observing time etc. carefully to optimize your chance to reach your scientific goals.
Before you begin writing a proposal, you should check whether any of your target sources have already been observed at the VLA. The NRAO routinely archives the raw (uncalibrated) visibility data from all VLA observations. General access to these data is restricted for 18 months after the end of the associated observing program. Thereafter, the raw data are available to any interested scientist. Apart from the large-scale NVSS and FIRST L Band surveys that are now in progress, calibrated and processed data remain the property of the original observer so are not automatically indexed or archived at the VLA. They may however be available from that observer, or even be on one of the NRAO CD-ROMs. .Catalogs of the observed sources, including relevant instrumental parameters, can be obtained by reading the Cumulative Observation List from the VLA Home Page at (http://www.nrao.edu/doc/vla/html/VLAhome.shtml), or from the MS-DOS PC database program VLASORS. The VLA Archive Database is a growing, but still incomplete, segment of this list that can be queried over the World-Wide-Web using an HTML forms interface ( http://info.aoc.nrao.edu/doc/vladb/VLADB.html, also accessible from the VLA Home Page). If you decide that the major parameters of an earlier observation are also appropriate for your work, you may either contact the original observers to use their calibrated data, or request use of the uncalibrated data from the VLA archive. Watch the NRAO Newsletter and the VLA Home Page for updates about the archive and associated software.
When writing the proposal, think about your calibration strategy in detail, as well as the target source observations. The total time you request should include all the on-source integration time that you need, plus enough time for any and all calibrations that you will do. Depending on the project, calibration time may need to be from 10% to 50% of the total. Filling out items 16 and 17 on the proposal cover sheet for each target, or for typical targets, will lead you to consider the issues discussed here. Your entries should show that the proposal is well suited to the requested configuration(s).
VLA observations may be scheduled for as little as half an hour at a time or for as long as several days. The median time that is scheduled varies from configuration to configuration, but is typically 6-8 hrs. Observations that are much longer than this median time will generally be harder to come by than observations that are much shorter, but there are no hard guideline in either direction. Recognize however that there is always more observing time proposed than can be scheduled, and that proposals for longer-than-usual observing times will probably have to generate more-than-usual scientific excitement to get as much time as they ask for. There is generally more pressure for observing time in the LST ranges of popular targets such as the Galactic Center and the Virgo Cluster.
The projected long term configuration schedule is published regularly in the NRAO Newsletter, the AAS Newsletter and in the VLA Observational Status Summary.
Proposals should be sent to the NRAO well before the deadline for the desired configuration(s).
Proposals can be submitted in two ways (note that FAXes are not acceptable):
Detailed instructions for submitting VLA proposals can be found on the World-Wide-Web at http://www.nrao.edu/administration/directors_office/tel-vla.shtml.
You need not wait until the deadline for a particular configuration before submitting a proposal. You might submit a proposal for an earlier deadline for two reasons--(a) the pressure of proposals for a given configuration influences the length of time that the VLA is scheduled to spend in the configuration, (b) early submission may let you respond to unfavorable comments from the referees before the scheduling committee assigns time for the requested configuration(s).